Synthesis and Crystal Structure Analysis of C60 Fulleride Dianions in Solvates of [A([2.2.2]crypt)]2[C60] (A = K, Rb, Cs)

Stephan D. Hoffmann, Thomas F. Fässler
2004 Zeitschrift für Naturforschung. B, A journal of chemical sciences  
Reduction of C60 with the alkali metals A = K, Rb and Cs in tetrahydrofuran as a solvent and addition of [2.2.2]crypt [1], dimethylformamide and cyclohexane lead to the formation of crystalline samples of [A([2.2.2]crypt)]2[C60](C6H12)2(C3H7NO)2(C4H8O)2 (A = K, Rb, Cs) 1a, 1b and 1c as major fractions. As a by-product of compound 1a, a second minor fraction containing [K([2.2.2]crypt)]2[C60](C3H7NO)4 2 was obtained. The structures of the four compounds have been determined by single-crystal
more » ... single-crystal X-ray analyses. The [C60]2− dianions are predominantly ordered. As the main structural motif the structures of compounds 1a, 1b and 1c contain pseudo-hexagonal layers of [C60]2− dianions. Compound 1c contains a rare example of a Cs+ sequestering [2.2.2]crypt molecule. The packing of the ionic units in compound 2 also shows layers of distorted hexagons formed by [C60]2− dianions which arranged in pairs with short contacts of 10.3 Å between their centers of gravity.
doi:10.1515/znb-2004-11-1231 fatcat:s26be7nitfexbfjuchq3h76dwy